<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <script src="https://cdn.jsdelivr.net/npm/vue@2.6.10/dist/vue.js"></script>
  <style>
    /*enter->enter-active->enter-to 从无到有
    leave->leave-active->leave-to 从有到无*/
    .v-enter-active {
      animation: bounce-in 1.5s;
    }

    .v-leave-active {
      animation: bounce-in 1.5s reverse;
    }

    @keyframes bounce-in {
      0% {
        transform: scale(0);
      }

      50% {
        transform: scale(1.5);
      }

      100% {
        transform: scale(1);
      }
    }
  </style>
</head>

<body>
  <!-- 动画 单元素/组件帧动画 -->
  <div id="app">
    <button @click="show=!show">按钮</button>
    <transition>
      <p v-if="show">hello vue</p>
    </transition>
  </div>
  <script>
    var app = new Vue({
      el: '#app',
      data: {
        show: true
      }
    })
  </script>
</body>

</html>